Multi-die integrated circuits (ICs) are a class of ICs in which multiple dies are placed within a single package. A multi-die IC also can be referred to as a “system in a package” or “SiP.” A multi-die IC can include circuit structures that allow the dies to communicate with one another within the single package at faster speeds than would be attainable were the dies to be implemented as separate ICs or as individual IC packages mounted on a printed circuit board.
For example, many modern ICs, including multi-die ICs, are capable of operating in the radio frequency (RF) range. Operating in the RF range can make implementing passive circuit elements such as inductors and capacitors within the IC structure desirable. The formation of high quality passive circuit elements within ICs, however, has been problematic.